Armory Research
Information on armory (device/Coat-of-Arms, badges) and design can be found in several places on the web, including the West Kingdom Herald's Handbook.

The following are some of them. Please note that just because someone has posted it on the web does not mean it is necessarily a good resource, you should always verify your information with a herald.

NOTE: Wikipedia, while an interesting place to start research, is not considered a valid research source by the College of Arms. Please do NOT print documentation from Wikipedia and mail with your documentation.

From the West Kingdom Herald's Handbook

Getting Advice on Heraldry (How to Help the College of Heralds Help You) A
Books on Armory A
A Very Basic Introduction to Heraldry A
Philosophical Roots of Heraldic Design A
Insta-Bounce Checklist A (A listing of armory decisions that will cause your submission to be immediately returned)
Reserved and Prohibited Charges A (Items you shouldn't try to register with the heralds)

The Following is a multi-part (it's not small) article that while aimed at Scribes is very good for anyone interested in heraldic design, as it talks about heraldry with the assumption that you're not a herald:
Heraldry For Scribes Part 1 A
Heraldry For Scribes Part 2 A
Heraldry For Scribes Part 3 A
Heraldry For Scribes Part 4 A
Heraldry For Scribes Part 5 A
Heraldry For Scribes Part 6 A
Heraldry For Scribes Part 7 A

From the Laurel Sovereign of Arms' website

Laurel "Education" Website
      Articles on armory and armorial design
Look for the sections "Articles on Blazonry" and "The Armory Submissions Process".

SENA -- Submissions Checklist
This is easier to read than SENA (the "Standards for Evaluation of Names and Armory") currently in effect in the College of Arms. This can be a useful place to go to check if your submission (name or armory) meets the requirements of the rules, without reading the rules themselves (which can be a bit arcane).

OSCAR -- Online System for Commentary And Response
This site allows even a visitor to see some of the commentary for submissions at the College of Arms level, including documentation for names, armory, etc. To see everything you might need to register an account, but visitors can see at least some of it.

Misc. Other Sites of Interest:

The Pictorial Dictionary of Heraldry as Used in the SCA -- a useful resource to show many charges and such that are used in SCA heraldry, including some items that are not allowed. In book form, this used to be called "The PicDic".

Websites about European Armory: (An Annotated Bibliography of Scottish Heraldic Materials)

Websites about Middle/Near East Armory: (Lots of good images, as well as some good text) (Article by Da'ud ibn Auda, also lots of good images, and Da'ud is a former Laurel Sovereign of Arms)

Websites about Far Eastern Armory: (An Essay on Mons, from the Laurel Sovereign of Arms website)

Book Heraldry Page Main Herald's Page

A -- Items with a red 'A' by them require the use of Adobe Acrobat Reader (freeware), downloadable from: Acrobat
-- Items that show this image by them are ones that are links to other websites ...
-- Items with a checkmark by them are pages you have visited ...